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Running Rich

5oh

Two Tone One Mustang
I don't know if I'm running rich or lean but my fuel economy is very poor.
 

wickedstangs

Chula Vista, CA
Staff member
Administrator
Okay I tested.

This time I got :

19 O

Separation code

41 C, 91 C

Ok we need to work on the KOEO test faults first... If you got CODE 19 and you are sure, you are going to have to do what @sdsubzero4 posted..

sdsubzero4 said:
Code 19 - Engine off - No Vehicle Power (pins 37 + 57) or bad PCM VPWR Diagnosis. This is a wiring problem that is from a bad ECC power relay, bad connection, bad fuse link or a bad computer. The ECC relay is located on top of the computer under the passenger side kick panel. Pull the connector off any fuel injector and measure the voltage on the red wire: if its 12 volts or better, the ECC relay is OK. If the ECC relay is OK, pull the kick panel off and measure the voltage at pins 37 & 57. If it is 12 volts or more, then the computer's diagnostic firmware has taken a dump and is defective.
Engine running - Erratic idle during test (reset throttle & retest) - Idle Set Procedures
 

5oh

Two Tone One Mustang
Ok we need to work on the KOEO test faults first... If you got CODE 19 and you are sure, you are going to have to do what @sdsubzero4 posted..
Okay I measure the voltage on a injector and it's at 12v. So to measure the pins I unplug the ecu turn the key on (not running) and measure the voltage of pins 37&57 on the ECM connector?
 

wickedstangs

Chula Vista, CA
Staff member
Administrator
Okay I measure the voltage on a injector and it's at 12v. So to measure the pins I unplug the ecu turn the key on (not running) and measure the voltage of pins 37&57 on the ECM connector?
no if you unplug it you will not see voltage go thru the PCM. You have to check both pins 37 & 57 not at the same time keep one side of your multimeter to ground and measure the voltage. Post up what you get.
 

5oh

Two Tone One Mustang
no if you unplug it you will not see voltage go thru the PCM. You have to check both pins 37 & 57 not at the same time keep one side of your multimeter to ground and measure the voltage. Post up what you get.
Okay so do I have to take the ecu out? And if I don't unplug the ecu then how do I test the pins?
 

wickedstangs

Chula Vista, CA
Staff member
Administrator
Okay so do I have to take the ecu out? And if I don't unplug the ecu then how do I test the pins?
you can remove the ECU just don't unplug it.. You should be able to get to the back of the pins..
 

5oh

Two Tone One Mustang
you can remove the ECU just don't unplug it.. You should be able to get to the back of the pins..
Okay so I unplugged the computer by accident I didn't know that the black piece can come off without removing the 10mm bolt. Anyways the car wasn't on so I plugged it back in (hopefully that doesn't affect the outcome)

I used a 12v test light. Only lights up if it 12v or more. So hopefully it's accurate.

I tested the injector wire and the 12v light lit up.
So the relay is good.

I tested the pins 37-57 (which are red wires) both lit up the 12v light


So what now?
 

5oh

Two Tone One Mustang
you can remove the ECU just don't unplug it.. You should be able to get to the back of the pins..
So after some research I came up with this:

------
Clearing Codes:
These codes are kept in memory for 40 warm up cycles. To clear the codes for purposes of testing or confirming repair, perform the code reading procedure. When the fault codes begin to be displayed, de-activate the test by either disconnecting the jumper wire or releasing the test button on the hand scanner. Stopping the test during code transmission will erase the continuous memory. Do not disconnect the negative battery cable to clear the codes; the keep alive memory will be cleared and a new code (19) will be stored for loss of PCM power.

Below will mention using a test light instead of the check engine light during the instructions you will read. If you would like to be up near the engine and pull the codes then hook up the jumper wire when instructed and as described above. NOW, hook up a professional or riged up test light from the positive batter terminal to the large test connector , bottom row 2nd pin (STO pin) counting left to right looking into the plug. When you follow the steps below, the test light will strobe codes and how to decode them will follow below. I have used a 12dc buzzer i got out of an old microwave that gives me an audible tone. This makes it easier to focus on the paperwork end of the task so im not looking back and forth at a light and paper second guessing myself.
------

I have been disconnecting the batter wire quite a bit lately to restart the computer. Like when I replaced the sensor and when I did the maf and to switch out the batter tray.
 

wickedstangs

Chula Vista, CA
Staff member
Administrator
So after some research I came up with this:

------
Clearing Codes:
These codes are kept in memory for 40 warm up cycles. To clear the codes for purposes of testing or confirming repair, perform the code reading procedure. When the fault codes begin to be displayed, de-activate the test by either disconnecting the jumper wire or releasing the test button on the hand scanner. Stopping the test during code transmission will erase the continuous memory. Do not disconnect the negative battery cable to clear the codes; the keep alive memory will be cleared and a new code (19) will be stored for loss of PCM power.

Below will mention using a test light instead of the check engine light during the instructions you will read. If you would like to be up near the engine and pull the codes then hook up the jumper wire when instructed and as described above. NOW, hook up a professional or riged up test light from the positive batter terminal to the large test connector , bottom row 2nd pin (STO pin) counting left to right looking into the plug. When you follow the steps below, the test light will strobe codes and how to decode them will follow below. I have used a 12dc buzzer i got out of an old microwave that gives me an audible tone. This makes it easier to focus on the paperwork end of the task so im not looking back and forth at a light and paper second guessing myself.
------

I have been disconnecting the batter wire quite a bit lately to restart the computer. Like when I replaced the sensor and when I did the maf and to switch out the batter tray.
are you still getting code 19? If code 19 comes back and you are getting 12v at both location pins 37 & 57 and the ECC relay is OK then the computer's diagnostic firmware has taken a dump and is defective. (might need a New CPU)
 

wickedstangs

Chula Vista, CA
Staff member
Administrator
Next thing is to get the CODE off of your CPU I might have an extra I can sell you. Need to check my junk drawer..:)
code.JPG
 
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